Improvement in converting articles made of iron into steel



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HIRAM C. FOLSOM, OF-JBANGOR, MAINE.

Letters Patent No. 101,250, dated .March 29, 1 870.

The Schedule referred to in these Letters Patent and making part of the lame.

To all whom it may concern:

Be it known that I, HIRAM O. FoLsoM, of Bangor, in the county of Penobscot and State of Maine, have invented new and useful Improvements in Converting Iron into Steel; and I do hereby declare that the following, taken in connection with the drawings which accompany and form part of this specification, is a description of my invention sufficient to enable those skilled in the art to which it appe-rtains to practice it.

This invention relates to the apparatus in which the iron is treated during the process of conversion into steel, the materials used to accomplish such conversion, and the mode' or process of treatment; and

The invention consists in providing the crucible in which the iron'is treated with a vertical tube extending from the bottom to a distance above the top suticient to enable the operator to open andclose the same outside the heating furnace.

This tube is provided with a stopcock or equivalent device, and, at itslower end, is perforated with a plulrality of small holes, all of which will be hereinafter more fully explained.

The inventiou'also-'consists in treating the iron, in a heated state, withcharcoal, prussiates of iron and potash; and further, in the order of time iu which these materials are brought to act upon the iron.

Figure 1 is a side 'elevationof the apparatus, and

Figure 2 is a vertical section thereof, taken on a line passing through the axis of the stop-cock.

Similar letters of reference indicate like parts in the several figures.

" In the drawings- A represents the Crucible, which is formed with a.

rebate around the inside of the top, into which fits the cover a a, which I construct with a thimble or short tube, as shown at b b.

c is a tube, which, near its lower extremity, is perforated with a suficient number of small holes, as showniu iig. 2.

A stop-cock, d, is fitted in the upper part of this tube, as shown.

B is the' fire-box or furnace, which has a grate, e e, fig. 2, and a cover, f f, through which is an aperture of sutlicient size to admit the stop-cock d, two slides, g g, fitting closely around the tube c.

In practice, the articles of iron to be converted into steel are packed in charcoal in crucible A, the tube c is placed in the position shown, when the crucible is hermetically sealed around the cover and tube, leaving the passage through the tube as the only communica tion with the inside of the Crucible.

WVhen the crucible is thus packed and sealed it is placed upon the grate-bars in furnace B, and either wood or charcoal is placed in the furnace around the Crucible and ignited, the cover ff is put in place, and the slides g g closed around the tube.

lhe stop-cock (l is left open until the heat has expelled the moisture and smoke from the charcoal in the Crucible, when itv is closed and the heating continued until the iron in treatment is brought to a red hea-t, when the stop-cock'is opened and the chemicals, consisting of four parts of prussiate of potash and one part of prussiate of iron, are passed down through tube c, and the stop-cock instantly closed.

'lhe heat acting upon the chemicals converts them into vapor, which, passing throigh the perforations in the tube, is diffused throughout the Crucible, uniting with the gas generated from the burning charcoal,.

and together acting upon the iron, convertit into steel to a depth proportionate to the amount of chemicals employed. Y

1f the iron be thin, or if it is desired to steel it only to a limited depth, one charge of the chemicals will usually be sufficient; but, when necessary, the chemicals may be applied more than once, or until the iron is converted to steel throughout. t Y

The practitioner is enabled to determine the proper time to close the cock after the tiring be commenced, by the absence of vapor and smoke escaping from the tube, and the incaudescence of the crucible indicates the proper time to introduce the-chemicals, as before described.

The quantity of chemicals to be used with a given quantity of irony being governed by the thickness of the articles and the depth to which it is desired to convert them, is readily determined by the practical t experience of the workman, and statements of quantities or proportions would not facilitate him in his work.

I employ as many tubes for the purpose of communicating with the interior of the crucible as the size thereof may render necessary. This method is peculiarly adapted to the conversion of small malleaf ble iron articles, such as cutlery, the constituent parts of lire-arms, and a great variety of small Wares, which are produced at a small cost, of malleable iron, then converted into steel and rendered equal to those forged from bars. It is also adapted to the conversion of all articles of wrought or malleable iron.

The advantages of the tube are that it obviates the former method of mingling the chemicals and charcoal together in the crucible with the articles to be converted before the Crucible was sealed, by which a large portion of the effect of the chemicals was lost,

and, if necessary, to repeat the application of the The sealing of the crucible now remainschemicals.

unbroken.

Having thus described my invention,

What I claim as new,- and desire to secure by Letters Patent, is

1. The process herein described for vconverting irony 3. The apparatus herein described,composed of the Crucible or heating vessel A, in combination `with the perforated tube C, as and for the purposes set forth.

HIRAM C. FOLSOM.

Witnesses A. L. SIMPSON, J. T. TBUNDY. 

